MY 2c is that it would be less sturdy like that. We have gotten to the point in car manufacturing where raw material costs are factored into car manufacturers decision making processes - so you don't tend to see thick bore walls (compared to some engines from 40 years ago at least!) on a lot of modern engines.

I think that if the factory could have saved some weight without affecting safety, they probably would have. not for performance sake, but for economic reasons. If they don't (admittedly extra machining can cost more than leaving some material on there) it's not always worth re-inventing the wheel.

If it was a streeter, you'd probably not worry about heat soak. But if it was to be raced, within reason, more disc 'material' (all else being equal) should = a better result, unless it was specifically in an area where it added mostly inertia with little extra heat energy transfer/issues.

It could also be the case that the manufacturing of the discs, whlist ok, isn't necessarily perfect, and having more meat around the stud/hub area is a little extra rigidity in case there is a slight flaw in the material itself. I admit this will be unlikely, but not implausible.

Best advice off the top of my head would be to try and find a cheap set second hand, modify them, and then do some back to back testing and see if there is any measurable improvement in peformance, braking, roadholding, whatever. I'd bank on it not doing zip, but the idea isn't 'insane' or 'out there'. It's just a matter of 'degree' - i.e. how much gain *if any* might be possible (and we could write an essay on just what parameters might be considered for gains and losses too!)

The slotting and drillng of rotors afaik isn't to reduce weight, it's to allow pad material or resin (for want of a better term) that is turning to a gas state with the heat, somewhere to expand and vent without pushing the pads off the disc (as weird as that sounds) and to keep the disc cleaner of debris by giving it an escape route of sorts

I think it was ferdinand porsche who quipped that a racing engine that didn't self destruct while the car was crossing the finish line was over-engineered. The point being that for a given application, lesser longevity can be acceptable and even desirable if it goes hand in hand with a performance gain (even be it short lived).